Woow what a beautiful ending, i liked this a lot! "If you don't have a place to belong to, make it yourself", that's something Midori finally learned 14 years after Tsugumi left, and it's only fitting for Haru to be the one to teach Midori that. They may be strangers cohabitating, but there's no need to put a label because it's a place they made for themselves, where they can truly be genuine.
Haru saying "see you later" when she was about to leave really shows the dichotomy between her and Tsugumi, with the latter completely leaving behind Midori. It shows that Haru is her own person, and just because she and her mother look the same doesn't mean they're the same. The parallelism is shown even more with both of them leaving during Spring, the season Midori hated. This time however, learning from the past, she doesn't have anything to be afraid of because Haru will definitely come back. Spring took her most precious person away, but in the end, spring once again gave Midori a loved one. Yay!
